1. Field of Invention
The present invention relates to wireless communication, and in particular, to the provision position estimation facilitated through a combination of different types of signal data.
2. Background
The desire for apparatuses to serve in a multitude of roles is driving designers to incorporate more functionality into emerging apparatuses. For example, wireless-enabled mobile devices are not only limited to the traditional conveyance of voice information during telephonic operations, but may also convey text, audio, video and other types of information for supporting a multitude of applications. Some applications may provide functionality on the surface that relies upon underlying wireless interaction for support. Obvious examples of such applications include programs that allow users to communicate directly with other users or resources, such as email, messaging services, Internet browsers, etc. There are also categories of applications that may provide services not directly related to user communication with other users or resources, but that still rely on underlying wireless exchange of information. Positioning-related services encompass a growing segment of applications that provide location services to users, such as mapping, route determination, tracking, etc., that rely upon wireless interaction for execution.
Positioning-related services may include known user-related applications, such as visual representations of locations or routes that may be displayed for users while underlying wireless communication is used to determine current apparatus position, direction, orientation, etc. However, other uses such as user/object tracking, location-specific social networking and commercial messaging, enhanced visual recognition, etc. are now becoming available that makes the ability to determine apparatus position a desirable feature to provide in mobile apparatuses. Positioning may be implemented using a variety of available technologies. For example, devices may incorporate global positioning system (GPS) receivers to receive signals from satellites for formulating an absolute (fixed) coordinate position. Terrestrial technologies (e.g., earth based cellular signals or short-range wireless interaction), while not as exact, may also be relied upon to resolve an absolute or relative (e.g., with respect to a signal source) apparatus position.
While GPS continues to be a popular positioning system for inclusion in wireless-enabled mobile apparatuses, it is a not viable solution for all circumstances. Implementing GPS requires dedicated hardware (e.g., a GPS receiver) and software. In mobile devices where every cubic millimeter of space may be allocated, circuitry dedicated to a single application may limit device design. GPS receiving subsystems also consume power and processing resources, which may be problematic in resource-limited mobile devices. With respect to performance, GPS may provide very accurate positioning information outdoors, but may exhibit unreliable performance in certain situations such as within structures (e.g., buildings) where physical barriers and other signal sources may cause interference impeding the ability of apparatuses to receive GPS signals.